In a disk drive system, especially the disk drive system arranged in a portable personal computer such as of notebook size, higher reliability is now required with respect to a shock during non-operation.
When a slider mounted on an actuator is moved from a parking position to a data area on a surface of a disk by the shock during non-operation of the disk drive system, the slider is attached to or harms a surface of the data area, which causes a fatal fault.
An actuator locking mechanism is known as a mechanism for holding the actuator in the parking position during non-operation and preventing the actuator from being oscillated and moved to the surface of the data area by the shock.
Considered in a recent disk drive system is a loading/unloading mechanism of the slider for the purpose of preventing the slider from being attached to a surface of the shunting area and of obtaining higher reliability with respect to the above described shock. The loading/unloading mechanism is such that the actuator is held by a component called a ramp provided near an outer periphery of the disk during non-operation of the disk drive system to thereby shunt the slider so as not to make contact with the surface of the disk.
One of the actuator locking mechanisms uses an inertial latching mechanism. In the actuator locking mechanisms using the inertial latching mechanism, the above described ramp of the loading/unloading mechanism or a magnetic locking mechanism or the like is usually used together as an actuator holding mechanism.
The inertial latching mechanism operates when the shock is applied on the disk drive system and latches the actuator by utilizing a force of inertia produced by the shock. This inertial latching mechanism can latch the actuator against a strong shock which cannot be dealt with only by the above described magnetic locking mechanism. The above described actuator holding mechanism holds the actuator when a slight shock is applied against which the inertial latching mechanism does not operate and increases reliability of the actuator locking mechanism.
An example of such an actuator locking mechanism using the inertial latching mechanism is shown in FIGS. 17 and 18. This actuator locking mechanism uses the ramp of the loading/unloading mechanism as the actuator holding mechanism.
In the inertial latching mechanism shown in FIG. 17, when the shock is applied such that an actuator 22 is counterclockwise oscillated (toward a disk 1), a latch lever 101 is oscillated counterclockwise around an oscillatory axis by a force of inertia and an engaging projection 102 abuts against a tip 26c of a coil arm of the actuator 22 to latch the actuator 22.
The inertial latching mechanism shown in FIG. 18 uses two balls 202, which push a latch lever 201 with the force of inertia, and the latch lever 201 latches the actuator 22 around the oscillatory axis (National Publication International Patent Application No. 1997-503608 specification).
An another example of the actuator locking mechanism using the inertial latching mechanism is provided with the inertial latching mechanism shown in FIG. 17 and a magnetic or electromagnetic locking mechanism for magnetically or electromagnetically latching the actuator as the actuator holding mechanism (Japanese Patent Laid-Open No. 8-339645 specification).
A component such as the actuator oscillatably provided on the oscillatory axis is generally accelerated linearly and angularly by the external shock. A force by linear acceleration (a translational force) is applied on a mass center of gravity and a force by angular acceleration (a couple of force) is applied mainly on the oscillatory axis. In a circle around the oscillatory axis which passes the mass center of gravity, a tangential component on the mass center of gravity of the circle is regarded as an effective component and a normal component of the mass center of gravity as an ineffective component. Involved in the oscillation of the above described component is the effective components of the angular and linear acceleration.